Lamp filament



FIG. 1 is a top, front, right side perspective view of a lamp filament showing our new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The bottom portion of the lamp filament shown in broken lines illustrates a portion of the design that forms no part of the claim. 

We claim the ornamental design for a lamp filament, as shown and described. 